Multiple section breast prosthesis

ABSTRACT

A lightweight breast prosthesis having a first section and a second section. The first section having a gel-like consistency simulating the human breast and the second section containing a density-reducing agent to provide a lightweight prosthesis which provides excellent mimicking of the human breast form.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a prosthesis and in particular, abreast prosthesis having dual sections which permit reduction in weightof the prosthesis while maintaining a prosthesis which mimics themovements of the human breast.

BACKGROUND OF THE INVENTION

There have been many attempts to produce a breast prosthesis for use bymastectomy patients. Such prosthesis are generally considered importantto the psychological health of the patient. However, in order to be ofbenefit, a prosthesis must mimic the human breast sufficiently such thatthe wearer believes that the presence of the prosthesis will beundetected by those the wearer meets. In addition to the movement andappearance of the prosthesis, it must also be easy to use andcomfortable to wear.

While prosthetic devices may be implanted, external prostheses haveachieved widespread acceptance because they do not require additionalsurgery, avoid the risks and health hazards of implants, are easilychanged such that the user may enjoy improvements in the technology, andare easy to use.

Early prosthetic devices utilized many different materials. Silicone gelbecame widely accepted for use in prosthesis because of its resilientproperties. At one time in the art, silicone prosthesis were preparedhaving a weight comparable to the weight of a human breast. It wasbelieved that this was advantageous because in the event that the userhad one natural breast and one prosthetic breast, that the balancing ofthe weight would be important. However, it was determined that matchingthe weight resulted in user discomfort. In U.S. Pat. No. 4,380,569, theuse of microspheres mixed into the silicone gel to reduce weight isdisclosed for the manufacturer of a prosthesis. While this methodachieved weight reduction, the introduction of glass spheres, thebonding of the spheres with the silicone gel, created a stiff productwhich did not mimic the human breast as well as silicone gel alone.

Thus, there has been a continued need for a prosthetic device whichmimics the movements of a human breast, which is lightweight andcomfortable to wear. The present invention has advantages of achievingreduction in weight to improve comfort for the patient while notsacrificing movement, feel and texture qualities of the prosthesis.

SUMMARY OF THE INVENTION

The invention is a lightweight breast prosthesis which providesexcellent mimicking of the human breast while achieving a reduction inweight of the prosthesis. The prosthesis has a first outer sectionextending from the back of the prosthesis and being disposed over aninner section. The inner section extends from the back to the insidesurface of the outer section. The outer section is comprised of a gelwhich has a consistency and feel similar to the human breast. The innersection utilizes a similar gel incorporating a density reducing agent toachieve predetermined reduced weight. The consistency of the outer andinner section can be varied as desired to achieve the desired balancebetween the characteristics of touch and feel of the total prosthesis,look of the total prosthesis and weight of the total prosthesis. Theconsistency of each section can vary as the dimensions of the sectionsvary. For example, if the volume of one section is much larger than thatof the other section, wider variations in consistency of the twosections typically can be employed.

In the preferred embodiment, the outer section and the inner section areheld within two flexible bags. The bags are preferably made frompolyurethane and incorporate a portion of the back of the prosthesis aspart of the bag. The outer section bag contains the gel of the outerlayer and the inner section bag contains a mixture of the gel anddensity reducing agent. The prosthesis is formed by taking a back sheetof polyurethane and attaching a polyurethane sheet of predeterminedshape to form the bag to contain the inner section. An outerpolyurethane sheet is attached to the back sheet such that the seamformed from the back sheet and the outer sheet is spaced apart from andoutside of the seam formed from by the back sheet and inner sheet.

Density reducing agent means a substance which has a density less thanthe density of the silicone gel used in the prosthesis, and which is ina form capable of distribution in small discrete portions. The densityreducing material may be entrapped air or gas bubbles, expanded perlite,styrofoam beads, glass microballoons or plastic microballoons.

The inner section of the prosthesis incorporates sufficient densityreducing material to reduce the density of the inner section from 5 to35% of the density the inner section would have if made entirely fromsilicone gel. The volume of the inner section is preferably from about20 to about 72% of the volume of the prosthesis. In the preferredembodiment, sufficient density reducing agent is added to reduce theweight of the total prosthesis from 2.5 to 25%.

In the preferred embodiment, the prosthesis is formed from having abacking made of the flexible film and having attached to one side aninner sheet the combination of the backing and inner sheet defining avolume for retaining the inner section of the prosthesis. Disposed onthe back sheet is an outer sheet disposed over the inner sheet whichtogether with the backing and the inner sheet defines the volume forsaid outer section. The prosthesis includes an outer section of solelysilicone gel having a consistency like that of a natural breast and aninner section made of silicone gel which contains a density reducingagent.

In preferred embodiments of the invention, the outer section encirclesthe back of the inner section. The width of the outer section at itsthinness portion is preferably about 0.5 inches more which has beenfound sufficient to provide a natural feel to the prosthesis.

The invention preferably contains the same type of silicone gel in bothsections and contains glass microspheres as a density reducing agent inthe inner section.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be described in reference to one ormore of the following drawings in which:

FIG. 1 is a cross-sectional area of the first embodiment of the presentinvention;

FIG. 2 is a cross-sectional area of the second embodiment of the presentinvention: and

FIG. 3 is a view of the prosthesis looking at the back of the prosthesiswhich will be positioned against the patient's chest.

DETAILED DESCRIPTION

The invention will now be described with reference to preferredembodiments and such description is not considered limiting of theinvention. In the drawings, like numbers refer to like items. Referringnow to FIG. 1, there is illustrated a breast prosthesis 10 in across-section. The prosthesis 10 has a back side 12 and an outer surface14. Outer surface 14 is in a shape resembling a human breast. Back 12 isshaped such that it may lay against the patient's chest. The prosthesishas two sections, an outer section 16 which extends from a portion ofback 12 and ends at outer surface 14. Outer section 16 covers innersection 18. Outer section 16 is roughly in the shape of a cone. Innersection 18 is made of a gel material in which a density reducing agent,such as glass microballoons 20, have been entrapped. Outer section 16and inner section 18 can be adhered, affixed together, or molded to eachother. The inner section 18 has a volume which is from about 20 to 72%of the volume of the entire prosthesis 10.

The composition of the prosthesis 10 is preferably of a gel-likematerial which is nontoxic and has properties which allow the formedprosthesis 10 to mimic natural breasts. The preferred material forproducing outer section 16 is silicone gel. Outer section 16 is formedentirely from a silicone gel. Various types of silicone gel are wellknown for use in breast prosthetics devices and any of these gels issuitable in the present invention. The gel may be purchased as atwo-resin component system, one component of the silicone gel containingthe cross-lining and is normally referred to in the trade as "siliconeB" and the other silicone resin component contains a catalyst toinitiate cross-linking (usually called "silicone A"). When the silicone"A" and "B" resins are mixed together and heated, a reaction involvingthe silicone, cross-linking agent, and catalyst result in thecross-linking and setting up of the silicone gel. As is known in theart, the stiffness of the resulting gel depends in large part upon theamount of cross-linker. Thus, the degree of cross-linking can be variedto achieve the desired feel.

The inner section 18 is preferably made of a silicone gel having glassmicroballoons 20 entrained therein as the density reducing agent. Themicroballoons are preferably the type which do not interfere with thecross-linking reaction of the gel components. Most preferably, themicroballoons are glass microspheres having a diameter of less thanabout 150 microns. Plastic microspheres are less desired because theyare not as durable and many can break during the mixing of microsphereswith the uncured gel. It has also been found that preferably the amountof microballoons used in inner section 18 is a quantity which results ina reduction in weight of the inner section 18 of about 35% or less fromthat if no density reducing were used. The specific quantity ofmicroballoons needed to achieve this weight reduction depends on manycharacteristics of the microballoons. The microballoons should be of asmall particle size such that they can be easily distributed throughoutthe entire inner section 18 and preferably are uniformly distributedthroughout the section. Small diameter microballoons are advantageous inthat they are more easily dispersed within the gel in a uniform manner.A uniform distribution of small diameter microballoons produces an innersection which has more uniform consistency than a section which wouldhave one or two large voids to reduce weight. It has been found thatusing a quantity of microballoons which produces a weight reduction ofthe inner section of more than about 35% is undesirable, as such amixture is generally stiffer than desirable and the bonding integrity ofthe gel portion suffers.

FIG. 2 is a cross-section of a second embodiment of the presentinvention. In FIG. 2, back 12 is formed by a backing sheet 30. Attachedto and extending from back sheet 30 is outer sheet 32. Outer sheet 32may be adhered to back sheet 30 in any suitable manner such as anadhesive or by welding. Thus, back sheet 30 and outer sheet 32 form anenclosure. Also extending from back sheet 30 is inner sheet 34. Innersheet 34 is attached to back sheet 30 by any suitable mechanism. Backsheet 30 and inner sheet 34 form a second bag which is partiallycontained within the bag formed by sheets 30 and 32. Thus, sheets 30, 34and 32 define the outer bag, which contains outer section 16. A portionof sheet 30 and sheet 34 form an inner bag which contains inner section18. As illustrated in FIG. 1, outer section 16 is preferably generallyin a shape resembling a cone which is disposed over inner section 18.The bonded seam of back sheet and the outer sheet is spaced apart andoutside of the bonded seam formed by back sheet and the inner sheet.

A rear view of either the prosthetic device of FIG. 1 or FIG. 2, itlooks generally shown in FIG. 3. (The figures are not being drawn toscale for purposes of illustration). Outer section 16 surrounds the backof the inner section 18. Outer section 16 forms an outer rear or backperimeter 40 which surrounds the rear or back perimeter 42 of innersection 18 such that the distance between perimeter 40 and 42 i.e.,width "w" can be of varying width around the prosthesis. The dimensionsalso vary with the size of the breast.

The outer section has a thickness which is sufficient to give theprosthesis the proper feel. Generally, it has been found that thethickness of the outer section at its thinnest point should be about 0.5inches or more to provide a feel similar to the natural breast.

In the embodiment of FIG. 1, a prosthetic may be made by making a moldhaving the shape of the outer surface 14, charging the mold withsufficient silicone gel to form section 16, closing the mold with a malemember in the shape of section 18. Thereafter, section 16 is cured andthe male section of the mold removed. The space occupied by the malemember of the mold in the shape of section 18 is then charged with amixture of gel reactants and microspheres, the mold closed with a memberhaving a shape to produce the desired back contour and then the gel isheated and cured. If the gel composition used for section 16 and used insection 18 are sufficiently similar, section 18 as it cures will bond tothe previously cured section 16.

In the embodiment of FIG. 2, the embodiment lends to the number ofmethods of formation. In one method, a mold may be lined with outersheet 32 then charged with sufficient reactants to form section 16. Thenthe mold then closed with a male member covered with sheet material 34.After section 16 is reacted the male member is removed and sufficientquantities to form a reactant to form section 18 are charged andreacted. Thereafter, back 30 can be adhered.

In another method, inner sheet 34 can be welded to backing sheet 30. Anopening can then be made and reactive gel components sufficient to formsection 18 injected into the sheet and reacted. Thereafter, sheet 32 canbe welded to backing 30 and a similar process employed to form curedsection 16, thereby forming an outer bag and an inner bag.Alternatively, the inner and outer bags are first formed. Access holescan then be provided to each bag, the inner bag is filled and then theouter bag can be charged with appropriate reactants to form section 18and 16 and thereafter cured. Before the cure, the charging holes can besealed. A method similar to that described in U.S. Pat. No. 5,370,688entitled "Encapsulated gel breast prosthesis and method of make"assigned to the assignee of this application.

Each method has certain advantages and disadvantages with respect to theother methods to form the breast prosthesis of the present invention.The embodiment of the present invention shown in FIG. 1 has certainadvantages and disadvantages with respect to the embodiment shown inFIG. 2 of the present invention. Thus, selection of the embodiment andthe particular process by which to make the embodiment are subject tomany subjective factors leaving the particular section to mostly amatter of one's choice.

It is preferred that in the embodiments of the present invention is thatthe outer section 16 and inner section 18 have substantially the samestiffness as measured by a penetrometer. A general preference is thatthe inner section 18 be slightly stiffer than outer section 16.

Suitable breast forms were made as exemplified in FIG. 2 of the presentapplication in which sheets 30, 32 and 34 were polyurethane sheets.Polymeric sheet materials made from polyesters and polyethers areuseful. The gel structure may be tested for appropriate consistency by apenetration test. The penetration of the gel components of the twosections may be measured using a Precision Scientific Penetrometer witha rod and foot assembly weight of 8 to 9 grams. The rod length is from6.5 to 6.7 inches and has a diameter of 0.12 to 0.13 inches. The footdiameter is from 0.245 to 0.255 inches and the thickness is from 0.13 to0.14 inches. The gel components are place in a Solo P3A plastic cup (3ounce cup). The cup is filled up to about 0.75 inches from the top. Thiswill generally result in a sample weight of about 50 grams for a samplewhich is entirely gel. A sample of the gel component with the densityreducing agent will have a weight less than 50 grams and the weight ofthe sample of this component will of course depend on the amount ofdensity reducing agent present. The sample is cured and then tested. Totest the sample the rod assembly is lower to the surface of the sampleso that it just touches he surface of the sample without making anindentation. The trigger on the Penetrometer is depressed and held for10 seconds. Thereafter the amount of penetration is read. The amount ofpenetration should be between 5.5 mm to 7.5 mm. In a preferredembodiment the penetration of the gel component for the inner section isequal to or lesser than the penetration measured for the gel componentfor the outer section. Thus, preferably the inner section is as stiff orstiffer than the outer section.

The volume of the inner section is preferably about 20 to about 75% ofthe volume of the entire prosthesis. The weight reduction for thecompleted prosthesis of the invention over one made entirely from gelwith no density reducing agents is from 5 to about 25%. Preferably theweight reduction of the complete prosthesis is from about 10 to 20%.

Also it is generally preferable that the microballoons be contained in asufficient quantity such that the weight of inner section 18 is betweenabout 5% to about 35% less than the weight of inner section 18 if it hadbeen made solely from the gel material. The weight of the outer sectionof the prosthesis is from about 65% to 84% of the total weight of theprosthesis. The volumes of the inner section and the outer section canbe varied as can the amount of the density reducing agent incorporatedin the inner section in order to achieve the desired balance betweenweight reduction and feel.

While the present invention has been described with reference topreferred embodiments, it will be understood that variations andmodifications can be made without departing from the scope of theinvention.

What is claimed is:
 1. A breast prosthesis comprising:(a) an outersection, said outer section comprising an outer surface shaped like ahuman breast and a first quantity of silicone gel, said outer surfacedefining a cavity filled with said first quantity of silicone gel, saidfirst quantity of silicone gel having a first penetration value; and (b)an inner section adjacent said outer section, said inner sectioncomprising a second quantity of silicone gel, said second quantity ofsilicone gel further comprising a density reducing agent, said secondquantity of silicone gel having a second quantity weight and a secondquantity volume, said density reducing present in sufficient amount sothat the second quantity weight is from about 5% to about 35% less thanthe weight of a comparative inner section comprising silicone gel in acomparative volume of silicone gel equal in volume to said secondquantity volume;said second quantity of silicone gel having a secondpenetration value less than said first penetration value, whereby sandouter section is less than said inner section in overall stiffness. 2.The prosthesis of claim 1 wherein the volume of the inner section is 20to 75% of the volume of the prosthesis.
 3. The prosthesis of claim 1wherein said density reducing agent is glass microspheres.
 4. A breastprosthesis comprising:(a) a back sheet of polymeric material; (b) anouter sheet attached to said back sheet and extending therefrom andbeing formable into the shape of a human breast; (c) an inner sheet ofpolymeric material welded to said back sheet at a predetermined distanceinside of a welded edge of said outer sheet and backing sheet; (d) anouter volume defined by the connection of said outer sheet, back sheetand inner sheet wherein said outer volume is filled entirely with afirst quantity of silicone gel; (e) an inner volume defined by theconnection of said inner sheet and said backing sheet wherein said innervolume is filled with a second quantity of silicone gel containingdensity reducing agents distributed therethrough contained within saidinner volume; and (f) said first quantity of silicone gel having a firstpenetration value and said second quantity of silicone gel having asecond penetration value, said second penetration value less than saidfirst penetration value, whereby said outer volume is less then saidinner section in overall stiffness.
 5. The prosthesis of claim 4 whereinsaid inner volume is 20 to 75% of the volume of the prosthesis.
 6. Theprosthesis of claim 4 wherein said density reducing agent is glassmicrospheres.
 7. A breast prosthesis comprising:(a) a back sheet ofpolymeric material; (b) an outer sheet attached to said back sheetextending therefrom and being formable into the shape of a human breast;(c) an outer volume filled with a first quantity of silicone gel; (d) aninner volume wherein said inner volume is filled with a second quantityof silicone gel containing density reducing agents distributedtherethrough contained within said inner volume; and (e) said firstquantity of silicone gel having a first penetration value and saidsecond quantity of silicone gel having a second penetration value, saidsecond penetration value less then said first penetration value, wherebysaid outer volume is less than said inner section in overall stiffness(f) said prosthesis having a weight from about 2.5% to about 25% of theweight of a comparative prosthesis without density reducing agents. 8.The prosthesis of claim 7 wherein said inner volume is 20 to 75% of thevolume of the prosthesis.
 9. The prosthesis of claim 7 wherein saiddensity reducing agent is glass microspheres.